update to eModbus 1.7.4

lib/eModbus/src/ModbusServerRTU.h

@@ -47,6 +47,9 @@ public:
   // Inquire protocol mode
   bool isModbusASCII();
 
+  // set timeout
+  void setModbusTimeout(unsigned long timeout);
+
   // Toggle skipping of leading 0x00 byte
   void skipLeading0x00(bool onOff = true);
 
@@ -61,8 +64,6 @@ protected:
   ModbusServerRTU(ModbusServerRTU& m) = delete;
   ModbusServerRTU& operator=(ModbusServerRTU& m) = delete;
 
-  inline void isInstance() { }           // Make class instantiable
-
   // internal common begin function
   void doBegin(uint32_t baudRate, int coreID, uint32_t userInterval);